<template>
	<view class="easy-loadimage" :style="[boxStyle]" :id="uid">
		<image class="origin-img" :style="[imageRadius]" :src="imageSrc" :mode="mode" v-if="loadImg&&!isLoadError"
			v-show="showImg" :class="{'no-transition':!openTransition,'show-transition':showTransition&&openTransition}"
			@load="handleImgLoad" @error="handleImgError">
		</image>
		<view class="loadfail-img" v-else-if="isLoadError"
			:style="{'background-image': `url(${urlDomain}crmebimage/presets/loadfail.png) no-repeat center`}"></view>
		<view :class="['loading-img','spin-circle',loadingMode,mode]" v-show="!showImg&&!isLoadError"></view>
	</view>
</template>
<script>
	// +----------------------------------------------------------------------
	// | CRMEB [ CRMEB赋能开发者，助力企业发展 ]
	// +----------------------------------------------------------------------
	// | Copyright (c) 2016~2025 https://www.crmeb.com All rights reserved.
	// +----------------------------------------------------------------------
	// | Licensed CRMEB并不是自由软件，未经许可不能去掉CRMEB相关版权
	// +----------------------------------------------------------------------
	// | Author: CRMEB Team <admin@crmeb.com>
	// +----------------------------------------------------------------------
	import {
		throttle
	} from '@/utils/validate.js'

	// 生成全局唯一id
	function generateUUID() {
		return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
			let r = Math.random() * 16 | 0,
				v = c == 'x' ? r : (r & 0x3 | 0x8);
			return v.toString(16);
		})
	}
	export default {
		name: 'easyLoadimage',
		props: {
			imageSrc: {
				type: String || null,
				default () {
					return '';
				}
			},
			mode: {
				type: String,
				default: "aspectFill"
			},
			loadingMode: {
				type: String,
				default: 'looming-gray'
			},
			openTransition: {
				type: Boolean,
				default: true,
			},
			viewHeight: {
				type: Number,
				default () {
					return uni.getSystemInfoSync().windowHeight;
				}
			},
			width: {
				type: String,
				default: ''
			},
			height: {
				type: String,
				default: ''
			},
			radius: {
				type: String,
				default: ''
			},
		},
		data() {
			const that = this;
			return {
				urlDomain: this.$Cache.get("imgHost"),
				uid: 'uid-' + generateUUID(),
				loadImg: false,
				showImg: false,
				isLoadError: false,
				borderLoaded: 0,
				showTransition: false,
				scrollFn: throttle(function() {
					// 加载img时才执行滚动监听判断是否可加载
					if (that.loadImg || that.isLoadError) return;
					const id = that.uid
					const query = uni.createSelectorQuery().in(that);
					query.select('#' + id).boundingClientRect(data => {
						if (!data) return;
						if (data.top - that.viewHeight < 0) {
							that.loadImg = !!that.imageSrc;
							that.isLoadError = !that.loadImg;
						}
					}).exec()
				}, 200)
			}
		},
		computed: {
			boxStyle() {
				return {
					width: this.width,
					height: this.height,
					borderRadius: this.radius
				}
			},
			imageRadius() {
				if (this.radius) {
					return {
						'border-radius': this.radius
					}
				}
			}
		},
		methods: {
			init() {
				this.$nextTick(this.onScroll)
			},
			handleBorderLoad() {
				this.borderLoaded = 1;
			},
			handleBorderError() {
				this.borderLoaded = 2;
			},
			handleImgLoad(e) {
				this.showImg = true;
				setTimeout(() => {
					this.showTransition = true
				}, 50)
			},
			handleImgError(e) {
				this.isLoadError = true;
			},
			onScroll() {
				this.scrollFn();
			},
		},
		mounted() {
			this.init()
			uni.$on('scroll', this.scrollFn);
			this.onScroll()
		},
		beforeDestroy() {
			uni.$off('scroll', this.scrollFn);
		}
	}
</script>

<style scoped lang="scss">
	.easy-loadimage {
		width: 100%;
		height: 100%;
		overflow: hidden;
		margin: auto;
		display: flex;
		justify-content: center;
	}

	.widthFix {
		min-height: 172px;
	}

	/* 官方优化图片tips */
	image {
		will-change: transform;
		overflow: hidden;
		object-fit: cover;
	}

	/* 渐变过渡效果处理 */
	image.origin-img {
		width: 100%;
		height: 100%;
		opacity: 0.3;
	}

	image.origin-img.show-transition {
		transition: opacity .5s;
		opacity: 1;
	}

	image.origin-img.no-transition {
		opacity: 1;
	}

	/* 加载失败、加载中的占位图样式控制 */
	.loadfail-img {
		height: 100%;
		background-size: 50%;
	}

	.loading-img {
		width: 100%;
		height: 100%;
	}

	/* 动态灰色若隐若现 */
	.looming-gray {
		animation: looming-gray 1s infinite linear;
		background-color: #e3e3e3;
	}

	@keyframes looming-gray {
		0% {
			background-color: #e3e3e3aa;
		}

		50% {
			background-color: #e3e3e3;
		}

		100% {
			background-color: #e3e3e3aa;
		}
	}

	/* 骨架屏1 */
	.skeleton-1 {
		background-color: #e3e3e3;
		background-image: linear-gradient(100deg, rgba(255, 255, 255, 0), rgba(255, 255, 255, 0.2) 50%, rgba(255, 255, 255, 0) 80%);
		background-size: 100rpx 100%;
		background-repeat: repeat-y;
		background-position: 0 0;
		animation: skeleton-1 .6s infinite;
	}

	@keyframes skeleton-1 {
		to {
			background-position: 200% 0;
		}
	}

	/* 骨架屏2 */
	.skeleton-2 {
		background-image: linear-gradient(-90deg, #fefefe 0%, #e6e6e6 50%, #fefefe 100%);
		background-size: 400% 400%;
		background-position: 0 0;
		animation: skeleton-2 1.2s ease-in-out infinite;
	}

	@keyframes skeleton-2 {
		to {
			background-position: -135% 0;
		}
	}
</style>